Excellence in Research: Role of the T3SS effector EseN of E. ictaluri in virulence and host immune response.

卓越研究：鲫鱼 T3SS 效应子 EseN 在毒力和宿主免疫反应中的作用。

• 批准号: 2100228
• 负责人: Lidiya Dubytska
• 金额: $ 74.47万
• 依托单位: Southern University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-07-01 至 2025-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2100228&HistoricalAwards=false
• 关键词: Excellence; Research; Role; T3SS; effector

Catfish are a food source around the world. Reducing fish loss is an essential task in the catfish industry for food security. Edwardsiella ictaluri is a bacterium, and it is a leading cause of catfish disease and loss. The goal of this project is to identify how this bacterium causes disease and death in catfish. We show that the EseN bacterial product is a virulence factor. Experiments here will identify how this EseN protein is involved in the disease development. These findings will increase basic knowledge about host-pathogen interactions. EseN has no equivalents in eukaryotes, and can therefore be an attractive target for indirect narrow-spectrum antibiotics. Findings from this project could be applied for disease prevention, disease control, and the development of a live-attenuated vaccine. Recently, Edwardsiellosis was also reported in other fish species that increases the importance of this work. The proposed work will also have a broad impact on research and research productivity at Southern University. It includes a mentoring program for undergraduate students and under-served high school students introduce them to research and to prepare them for careers in the Biological Sciences. The goal of this work is to determine the molecular mechanism(s) that the E. ictaluri T3SS effector EseN employs to accomplish its impact as a virulence factor on host physiology. This will be accomplished by investigating EseN modulation of host cell gene expression, determining EseN-host protein interactions, establishing phenotypic changes associated with specific gene mutations, and determining expression of genes involved in the host innate immune response. The E. ictaluri T3SS effector EseN is similar to Shigella OspF and Salmonella SpvC, which selectively dephosphorylate extracellular signal regulated kinase 1/2 (ERK1/2), p38, and c-Jun-N-terminal/stress-activated protein kinase (JNK) during infections, resulting in inactivation of mitogen-activated protein kinase (MAPK) signaling pathways. The EseN amino acid similarity to these other effectors, however, does not ensure similar activity, even if the biochemical activity of the homologous proteins is the same. Indeed, we find that EseN also targets the major vault protein and potentially phosphatidylinositide 3-kinase (PI3), in addition to ERK1/2. This demonstrates unique functions of EseN that are not described in its homologs. When these data are combined with the demonstrated high level of attenuation of an EseN knock-out mutant, we hypothesize that EseN is a major virulence factor that plays an essential role in manipulating host cytokine production and limiting induction of the host innate and adaptive immune responses. This project is jointly funded by Excellence in Research (EiR), and the Established Program to Stimulate Competitive Research (EPSCoR).This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

鲶鱼是世界各地的一种食物来源。减少鱼类损失是确保食品安全的一项基本任务。Edwardsiella ictaluri是一种细菌，它是造成鲶鱼疾病和损失的主要原因。该项目的目标是确定这种细菌是如何导致鲶鱼患病和死亡的。我们证明埃森细菌产物是一个毒力因子。这里的实验将确定这种Esen蛋白是如何参与疾病发展的。这些发现将增加关于宿主-病原体相互作用的基本知识。Esen在真核生物中没有等价物，因此可以成为间接窄谱抗生素的有吸引力的目标。该项目的发现可应用于疾病预防、疾病控制和开发减毒活疫苗。最近，爱德华氏菌病在其他鱼类中也有报道，这增加了这项工作的重要性。拟议的工作还将对南方大学的研究和研究生产力产生广泛影响。它包括为本科生和未得到充分服务的高中生提供指导计划，向他们介绍研究，并为他们在生物科学领域的职业生涯做好准备。本工作的目的是确定E.ictaluri T3SS效应子Esen作为毒力因子对寄主生理产生影响的分子机制(S)。这将通过研究Esen对宿主细胞基因表达的调控，确定Esen与宿主蛋白的相互作用，建立与特定基因突变相关的表型变化，以及确定参与宿主先天性免疫反应的基因的表达来实现。E.ictaluri T3SS效应子Esen类似于志贺氏菌OSPF和沙门氏菌SpvC，在感染过程中选择性地去磷酸化细胞外信号调节激酶1/2(ERK1/2)、p38和c-Jun-N末端/应激激活的蛋白激酶(JNK)，导致丝裂原激活的蛋白激酶(MAPK)信号通路失活。然而，Esen氨基酸与这些其他效应器的相似性并不能确保相似的活性，即使同源蛋白质的生化活性是相同的。事实上，我们发现，除了ERK1/2外，Esen还针对主要的拱顶蛋白和潜在的磷脂酰肌醇3-激酶(PI3)。这显示了Esen的独特功能，这些功能在其同源基因中没有描述。当这些数据与Esen基因敲除突变体的高水平衰减相结合时，我们假设Esen是一个主要的毒力因子，在操纵宿主细胞因子的产生和限制宿主先天和获得性免疫反应的诱导方面发挥重要作用。该项目由卓越研究计划(EIR)和已建立的激励竞争性研究计划(EPSCoR)共同资助。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。